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500,000 people injured by Asian tsunami

Near Khao Lak, about 100 kilometres north of Phuket, Thailand, volunteers sort bodies and place them into bags before taking them to the morgue, where a DNA sample is taken

(Image&colon; Leon Schadeberg/Rex Features)

By Shaoni Bhattacharya

Up to 500,000 people may have been injured in the tsunami which hit south east Asia on Sunday 26 December, the World Health Organization warned on Tuesday. This is in addition to the current estimated death toll of 150,000. And the region faces a further “health disaster” if access to clean drinking water is not resumed soon, the agency says.

Between three and five million people are without access to basic resources such as clean water, shelter, food, sanitation and healthcare after the world’s most powerful earthquake in 40 years shook the region and generated a colossal tsunami. The wave hit coastal regions in 12 countries in total, with Indonesia, Sri Lanka, India and Thailand the worst affected.

But fears are growing that the surviving populations are now at risk of disease outbreaks. “Millions of people are now under serious threat as a result of damaged water and sanitation systems, sea water contamination and the congested and crowded conditions of the displaced,” warns a WHO situation report, published on 3 January.

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“A potential death toll of 50,000 due to diarrhoea and other disease is not at all unreasonable,” warned David Nabarro, a senior WHO official, on Saturday.

“That’s absolutely feasible,” agrees Valerie Curtis, an epidemiologist and hygiene specialist, and director of the Hygiene Centre at the London School of Hygiene and Tropical Medicine, UK. “That’s the worst case scenario.”

Overcrowded shelters

No official epidemics have been declared but hundreds of cases of acute diarrhoea are being reported in Thailand and the Maldives. Survivors living in overcrowded temporary shelters are also at particular risk of acute respiratory diseases such as pneumonia, warns the WHO. “But diarrhoea alone can kill a child in a few hours if they are dehydrated,” says Fadela Chaib, a WHO spokeswoman.

Curtis cautions that a “knee-jerk reaction” to such disaster scenarios is to concentrate on providing pure drinking water. “Sanitation and hygiene is the issue,” she told New Scientist.

“Most of the water is coming from high ground, and is probably not affected by the tsunami,” she says. “Providing soap and water for washing hands is vastly more important than providing pure clean water, unless you know the water is contaminated by sewage.”

Diarrhoea is a symptom of gastroenteric diseases, caused by about 20 different organisms. These are spread through contact with human faeces. One common cause is Shigella, says Curtis. This has a very low infectious threshold – “you don’t need many organisms to fall sick”. Others include Campylobacter, Escherichia coli and Salmonella. Research by her team has shown that hand washing can cut the risk of transmission by 47%.

Young and old

Nick Beeching, a consultant in infectious disease at the Liverpool School of Tropical Medicine, UK, says that the young and very old will be most at risk from the effects of waterborne diseases because they are least able to tolerate the dehydration which comes with diseases which cause vomiting.

“At the moment there is not enough clean water to rehydrate them,” he says. “Sadly this means that a lot of people are going to die of illnesses which would not normally be life threatening.”

The WHO has also warned that overcrowded conditions will increased the risk of measles, influenza and meningitis outbreaks. It recommends that measles vaccines be given immediately to all infants and children between six and 59 months of age.

Campaigns have already started in Sri Lanka and the south Indian state of Kerala. “Measles is a deadly threat to children living in crowded camps,” says Marzio Babille, UNICEF’s chief of health in India. “It spreads quickly, killing children, or severely weakens their immune systems. Those children are then too weak to fight off other diseases, leading to more deaths. It’s a vicious circle. But we can head it off with a good round of immunisation and vitamin A.”

Cholera and typhoid – spread through contaminated water – are also a concern, but mass vaccination is not needed says the WHO. “The most practical and effective strategy to prevent cholera and typhoid is to provide clean water and adequate sanitation,” it says. Millions of water purification tablets have been sent to the region, along with sanitation engineers to try and re-build water and sanitation infrastructures.